RECESSED LEAF SPRING SUSPENSION SYSTEM
A leaf spring suspension system for a vehicle includes an axle. The leaf spring suspension system includes a leaf spring having a top side, a bottom side, and a pair of side edges, wherein at least one of the side edges defines a pair of recesses extending inwardly from the side edge. The leaf spring suspension system also includes a clamping assembly operatively coupling the leaf spring to the axle, the clamping assembly comprising a pair of U-shaped bars, wherein a portion of the U-shaped bars is disposed within the pair of recesses of the leaf spring.
This application claims the benefits of priority to U.S. Provisional Patent Application Ser. No. 63/244,793, filed on Sep. 16, 2021, the disclosure of which is incorporated by reference herein in its entirety.
FIELD OF THE INVENTIONThis invention relates generally to leaf spring suspension systems for vehicles and, more particularly, a leaf spring having a recess feature.
BACKGROUNDLeaf spring systems have for many years been used for the suspension of wheeled vehicles. The central element of a leaf spring suspension system for a vehicle is termed a “semi-elliptical” spring configured as an arc-shaped length of spring steel having a substantially rectangular cross-section. At the center of the arc is provided an arrangement for coupling to the axle of the vehicle. At the ends are provided coupler holes for attaching the spring to the vehicle body. For heavy vehicles, leaf springs are stacked on one another to form layers of springs of different lengths. Leaf springs are still used in heavy commercial vehicles and railway carriages. In the case of very heavy vehicles, leaf springs provide the advantage of spreading the load over a larger region of the vehicle's chassis. A coil spring, on the other hand, will transfer the load to a single point.
The well-known Hotchkiss drive employs a solid axle that is coupled at its ends to the centers of respective semi-elliptical leaf springs. A clamping assembly that includes several components attaches the leaf spring(s) to the axle. The clamping assembly typically includes a pair of U-bolts that extend along edges of the leaf spring to secure the overall assembly together. However, if the spring width is increased for any reason, such as a design change in a vehicle program, all clamping assembly components may be required to be changed, including an axle perch welded to the axle. These changes involve major changes that increase the time, complexity and possibly cost for various suspension programs.
SUMMARY OF THE INVENTIONAccording to one aspect of the disclosure, a leaf spring suspension system for a vehicle includes an axle. The leaf spring suspension system includes a leaf spring having a top side, a bottom side, and a pair of side edges, wherein at least one of the side edges defines a pair of recesses extending inwardly from the side edge. The leaf spring suspension system also includes a clamping assembly operatively coupling the leaf spring to the axle, the clamping assembly comprising a pair of U-shaped bars, wherein a portion of the U-shaped bars is disposed within the pair of recesses of the leaf spring.
According to another aspect of the disclosure, a method of designing a clamping assembly for a vehicle leaf spring suspension is provided. The method includes determining a width and thickness of a leaf spring. The method also includes determining a shape and dimension of a recess defined by a side edge of the leaf spring, the recess configured to receive a portion of a leg of a clamp bar therein.
These and other advantages and features will become more apparent from the following description taken in conjunction with the drawings
The subject matter which is regarded as the invention is particularly pointed out and distinctly claimed in the claims at the conclusion of the specification. The foregoing and other features, and advantages of the invention are apparent from the following detailed description taken in conjunction with the accompanying drawings in which:
Referring to
The vehicle suspension system 10 includes a leaf spring arrangement 50. The leaf spring arrangement 50 refers to a single leaf spring in some embodiments and a plurality of leaf springs in other embodiments. In a multiple leaf spring arrangement, the leaf springs are stacked and operatively coupled to each other. Regardless of whether a single leaf spring is provided or if a plurality of leaf springs are present, the leaf spring arrangement 50 is located along, and coupled to, the axle 16.
The leaf spring(s) may be referred to as “semi-elliptical” springs configured as arc-shaped length segments. The leaf spring(s) are formed of a composite material to achieve a lighter weight of the system, relative to metal alternatives. However, it is contemplated that other materials are employed to form the leaf spring(s). For example, the leaf springs disclosed herein may be formed of a composite material, one or more metals, reinforced polymers, and other multi-material combinations. For purposes of clarity, a single leaf spring is described in detail herein and is referred to with numeral 52. It is to be appreciated that the disclosed embodiments may be applicable to more than one leaf spring in a multi-spring arrangement.
Disposed between a first end 54 and a second end 56 of the leaf spring 52 is a clamping assembly 60 to operatively couple the leaf spring 52 to the axle 16. The leaf spring 52 is operatively coupled at ends 54, 56 to the chassis rail in some embodiments. In particular, the leaf spring 52 is coupled to the chassis rail with any suitable coupling element. In some embodiments, the leaf spring 52 is operatively coupled at its ends 54, 56 to the chassis rail with an eye spring bushing arrangement 57.
Referring now to
Referring now to
The recesses 70 (only one shown in enlarged views of
As described above, the recesses 70 accommodate the U-shaped rods 62 therein when a widening of the leaf spring 52 is desired. Referring to
To reinforce the scallop shaped wall 82 region of the recess 70 and to reduce stress concentration, different fiber arrangements may be utilized in the scallop shaped wall 82 region. In some embodiments, the reinforcement fiber arrangement may be disposed in the scallop shaped wall and all or part of the recess wall 80. In other words, the reinforcement structure may be partial or complete along the structural walls that define the recess 70 and the associated scallop. For example, woven, non-crimped in a variety of directions, meshed, rovings and knitted fabrics at 2D and 3D level may be provided (
The embodiments disclosed herein enable vehicles to use wider leaf springs while vehicle hardware modifications are eliminated or reduced. This promotes carryover of vehicle components between current and new platforms and reduces new suspension development cycles by fitting in current vehicle architectures. The embodiments allow simplification of sub-system and vehicle evaluation due to the carry over components. The embodiments avoid an increase in clamp group weight (assembly and components) due to maintaining OE width at the axle perch.
Although the invention has been described in terms of specific embodiments and applications, persons skilled in the art may, in light of this teaching, generate additional embodiments without exceeding the scope or departing from the spirit of the invention described herein. Accordingly, it is to be understood that the drawing and description in this disclosure are proffered to facilitate comprehension of the invention, and should not be construed to limit the scope thereof
Claims
1. A leaf spring suspension system for a vehicle comprising:
- an axle;
- a leaf spring having a top side, a bottom side, and a pair of side edges, wherein at least one of the side edges defines a pair of recesses extending inwardly from the side edge; and
- a clamping assembly operatively coupling the leaf spring to the axle, the clamping assembly comprising a pair of U-shaped bars, wherein a portion of the U-shaped bars is disposed within the pair of recesses of the leaf spring.
2. The leaf spring suspension system of claim 1, wherein the pair of recesses comprises an elliptical geometric cross-section.
3. The leaf spring suspension system of claim 1, wherein the pair of recesses comprises a circular geometric cross-section.
4. The leaf spring suspension system of claim 1, wherein the pair of recesses is defined by a recess wall, wherein a top region of the recess is defined by a scallop shaped wall extending away from the recess wall.
5. The leaf spring suspension system of claim 4, wherein the scallop shaped wall at the top region is a curved segment connecting the recess wall to the top side of the leaf spring.
6. The leaf spring suspension system of claim 4, wherein the scallop shaped wall at the top region is a planar angled segment connecting the recess wall to the top side of the leaf spring.
7. The leaf spring suspension system of claim 4, wherein a bottom region of the recess is defined by a scallop shaped wall extending away from the recess wall.
8. The leaf spring suspension system of claim 7, wherein the scallop shaped wall at the bottom region is a curved segment connecting the recess wall to the bottom side of the leaf spring.
9. The leaf spring suspension system of claim 7, wherein the scallop shaped wall at the bottom region is a planar angled segment connecting the recess wall to the bottom side of the leaf spring.
10. The leaf spring suspension system of claim 1, wherein the leaf spring is formed of a composite material.
11. The leaf spring suspension system of claim 1, wherein the leaf spring is formed of at least one of metal(s), reinforced polymers, and other combination materials.
12. The leaf spring suspension system of claim 2, wherein the leaf spring is formed of a composite material, the strength of the leaf spring is configured to be increased with a tailored fiber placement arrangement disposed within at least a portion of the recess.
13. A method of designing a clamping assembly for a vehicle leaf spring suspension comprising:
- determining a width and thickness of a leaf spring; and
- determining a shape and dimension of a recess defined by a side edge of the leaf spring, the recess configured to receive a portion of a leg of a clamp bar therein.
14. The method of claim 13, wherein determining the width and thickness of the leaf spring is based on a section modulus of the leaf spring.
15. The method of claim 13, wherein determining the shape and dimension of the recess is based on material stress limit calculations.
Type: Application
Filed: Sep 15, 2022
Publication Date: Mar 16, 2023
Inventors: Brent Collyer (Northville, MI), Jose Guadalupe Ruiz Juarez (Piedras Negras), Juan Pablo García Osuna (Nava), Angel Fabian Mijangos (Piedras Negras), Eddy Alfaro Lopez (Piedras Negras), Juan Luis Zapata Nava (Piedras Negras)
Application Number: 17/945,484